I. FIELD OF THE INVENTION
The present invention relates to data communications.
II. DESCRIPTION OF THE RELATED ART
Wireless communications systems employ a number of geographically distributed, cellular communication sites or base stations. Each base station supports the transmission and reception of communication signals to and from stationary or fixed, wireless communication devices or units. Each base station handles communications over a particular region commonly referred to as a cell/sector. The overall coverage area for a wireless communications system is defined by the union of cells for the deployed base stations. Here, the coverage areas for adjacent or nearby cell sites may overlap one another to ensure, where possible, contiguous communications coverage within the outer boundaries of the system.
When active, a wireless unit receives signals from at least one base station over a forward link or downlink and transmits signals to at least one base station over a reverse link or uplink. Several approaches have been developed for defining links or channels in a cellular communication system. These schemes include, for example, TDMA (time-division multiple access), and CDMA (code-division multiple access).
In TDMA communication systems, the radio spectrum is divided into time slots. Each time slot allows only one user to transmit and/or receive. Thusly, TDMA requires precise timing between the transmitter and receiver so that each user may transmit their information during their allocated time.
In CDMA communications systems, different wireless channels are distinguished by different channelization codes or sequences. These distinct channelization codes are used to encode different information streams, which may then be modulated at one or more different carrier frequencies for simultaneous transmission. A receiver may recover a particular stream from a received signal using the appropriate code or sequence to decode the received signal.
Referring to FIG. 1, a typical network 10 supportive of wireless communications is shown. Here, network 10 may accommodate one of a number of architectures, including Universal Mobile Telecommunications System (“UMTS”), for example. Network 10 may be divided into a radio access network (“RAN”) 12 and a core network 14. RAN 12 includes equipment used to support wireless interfaces 16a and 16b between a wireless unit 18a and 18b and network 10. RAN 12 further comprises a plurality of Node Bs or base stations 20a through 20c, as well as a number of radio network or base station controllers (“RNC”) 22a and 22b. The signaling exchange between the Node Bs and RNCs is commonly referred to as the Iub interface, while the interface between RNCs themselves is commonly referred to as the Iur interface. The transport mechanism of both the Iub and Iur interfaces is generally based on asynchronous transfer mode (“ATM”).
Core network 14 includes network elements that support circuit based communications, as well as packet-based communications. In establishing a circuit channel to handle circuit-based communications between the wireless unit 18b and a public switched telephone network (“PSTN”) 24 or another wireless unit, base station 20b receives (in the uplink) and transmits (in the downlink), the coded information (circuit voice or circuit switched data) over the wireless interface or link 16b. RNCs 22a and 22b may each perform a number of functions, including frame selection, encryption, and handling of access network mobility, for example. In the above example, RNC 22b may forward the circuit voice and circuit switched data over a network, such as an asynchronous transfer mode (“ATM”)/Internet Protocol (“IP”) network to a mobile switching center (“MSC”) 30. MSC 30 is responsible for call processing and macromobility on the MSC level. MSC 30 establishes the connectivity between wireless unit 18b and PSTN 24.
In establishing a packet channel to handle packet-based communications between wireless unit 18a and a packet data network (“PDN”) 34, such as the Internet, base station 20a receives (in the uplink) and transmits (in the downlink), the coded information over the wireless interface or link 16a. In the uplink direction, RNC 22a reassembles the packets as sent by wireless unit 18a and forwards them to an SGSN 40. In the downlink direction, RNC 22a receives the packets and segments them into the right size packet to be transferred to the base station, which may perform its processing and the data across the wireless link 16a. SGSN 40 provides packet data session processing and macromobility support for network 10. SGSN 40 establishes connectivity between wireless unit 18a and PDN 34. A GGSN 42 is the gateway to external PDNs. GGSN 42 acts upon requests from SGSN 40 for packet data protocol (PDP) session establishment.
For voice applications, conventional cellular communication systems employ dedicated links between a wireless unit and a base station. Voice communications are delay-intolerant by nature. Consequently, wireless units in wireless cellular communication systems transmit and receive signals over one or more dedicated links. Each active wireless unit generally requires the assignment of a dedicated link on the downlink, as well as a dedicated link on the uplink.
With the explosion of the Internet and the increasing demand for data, resource management has become a growing issue in cellular communication systems. Next generation wireless communication systems, such as those employing High Speed Downlink Packet Access (“HSDPA”), are expected to provide premium data services in support of Internet access and multimedia communication. Unlike voice, however, data communications may be potentially bursty yet relatively delay tolerant. The system for data communications, as such, may not be efficient with dedicated links on the downlink or the uplink. A more efficient data communication system may be enabled if the system employs one or more channels to be shared by a number of wireless units. By this arrangement, each of the wireless units on the downlink shares available resources, where the downlink transmission is scheduled to the user(s) through a resource management process. Resources to be managed in the downlink include, for example, the allocated transmit power by the Node B, the channelization codes, and/or the interference created by each user to other users in the same sector or cell, as well as in other sectors or cells.
The general management of resources on the downlink at a Node B offering HSDPA services is performed by a radio network controller—RNC 22a and/or RNC 22b in FIG. 1, for example. More particularly, an RNC determines the allocation of transmit power, for example, for each Node B supporting HSDPA services. Thusly, the distribution of a Node B's resources between HSDPA and non-HSDPA applications is determined by the RNC. For the purpose of the present disclosure, non-HSDPA applications include voice and other non-delay tolerant traffic services, which are afforded priority by the RNC over HSDPA services by means of dedicated channels. Consequently, an exemplary RNC may determine to allocate seventy percent (70%) of a Node B's power for voice services, for example, and thusly a maximum of thirty percent (30%) for HSDPA services.
Over time, however, the allocation and distribution of the resources between voice and HSDPA services may require modification. The demand for voice services, however, may diminish in comparison with the need for resources to support HSDPA services. For example, the demand for voice services may drop such that a Node B may only require forty percent (40%) of the transmit power. The efficiency of the Node B's transmit power, thusly, may become an issue of concern if, in this example, the HSDPA services are not allowed to employ the unused voice services transmit power.
Presently, any changes to the allocation and distribution are made statically by the RNC, in a centralized manner. The static nature of these changes may take a considerable period of time. This time lag may be attributed, for example, to the need for measuring and assessing the statistical usage of voice and/or HSDPA services over hours and/or days. This is further buttressed by the relatively high latency period between the RNC and the Node B. For example, a measurement inquiry might first be initiated by the RNC to the Node B, and the response to such an inquiry thereafter might be transmitted by the Node B back to the RNC. Only after these measurements are performed might the RNC determine that the allocation and distribution inefficient, before the appropriate changes are made.
Consequently, the present centralized allocation and distribution of the Node B's control resources by the RNC is inefficient and time consuming given the potential fluctuations in the demand for services. Therefore, a need exists for a more efficient method to facilitate changes in the management of a base station's resources in response to changes in demand for services.